Húsvörðurinn sagði að dyrasíminn hefði verið bilaður í þrjátíu daga.

Because Icelandic usually adds the definite article to the end of the noun instead of using a separate word like English the.

• húsvörður = caretaker / janitor

• húsvörðurinn = the caretaker

• dyrasími = intercom / door phone
• dyrasíminn = the intercom

So both nouns are definite here.

Húsvörðurinn is the nominative singular definite form of húsvörður.

It literally means something like:

• caretaker
• building manager
• janitor

The exact English translation depends on context, but grammatically it is the caretaker.

It is the subject of the main clause:

• Húsvörðurinn sagði ... = The caretaker said ...

It is a compound noun:

• dyra- = of doors / door-
• sími = telephone / phone

So dyrasími means something like:

• door phone
• entry phone
• intercom

Then the definite article is added:

• dyrasími → dyrasíminn = the intercom

This is very common in Icelandic: long compounds are built from smaller words.

Here að means that and introduces a subordinate clause:

• Húsvörðurinn sagði að ...
• The caretaker said that ...

In English, that is often optional:

• He said that the intercom...
• He said the intercom...

In Icelandic, að is very commonly used in this structure.

hefði verið is the past subjunctive form, and it is very common in indirect speech after verbs like segja when reporting what someone said.

So:

• sagði að dyrasíminn hefði verið bilaður ...

means roughly:

• said that the intercom had been broken ...

Why subjunctive? Because Icelandic often uses the subjunctive in reported speech rather than direct quotation. It helps show that this is someone’s reported statement, not the speaker’s own direct assertion.

Very roughly:

• hann sagði: „Dyrasíminn er bilaður.”
  = direct speech

• hann sagði að dyrasíminn hefði verið bilaður
  = indirect/reported speech

Learners often notice that English does not mark this as clearly, but Icelandic does.

It is a compound verb form:

• hefði = subjunctive past of hafa (have)
• verið = past participle / supine form of vera (be)

Together with bilaður, it forms a meaning like:

• had been broken
• was said to have been broken

So the structure is:

• hefði verið bilaður

This is not a passive. It is more like a be + adjective/past participle construction describing a state.

Because bilaður agrees with dyrasíminn.

The noun dyrasíminn is:

• masculine
• singular
• nominative

So the adjective/predicate form must match:

• masculine singular nominative: bilaður

Compare:

• síminn er bilaður = the phone is broken
• hurðin er biluð = the door is broken
• tækið er bilað = the device is broken

This kind of agreement is very important in Icelandic.

Yes, in this sentence it functions as a predicate adjective, even though it comes historically from the verb bila (to break down / malfunction).

So:

• dyrasíminn var bilaður
• the intercom was broken / out of order

This is similar to English expressions like:

• The machine is broken
• The phone is damaged

In Icelandic, forms like bilaður often behave like normal adjectives and agree with the noun they describe.

Icelandic often uses í + accusative to express duration of time.

So:

• í þrjátíu daga = for thirty days

Here:

• þrjátíu = thirty
• daga = accusative plural of dagur (day)

This is a very common pattern:

• í tvo daga = for two days
• í viku = for a week
• í langan tíma = for a long time

Even though í often means in or into, with time expressions it can mean for.

Because after í in a duration expression, Icelandic uses the accusative.

The noun dagur has different case forms. Here we need the accusative plural:

• nominative plural: dagar
• accusative plural: daga

Since þrjátíu does not change form here, the case is mainly visible on daga.

So:

• í þrjátíu daga = for thirty days

The basic structure is:

• Húsvörðurinn — subject
• sagði — verb
• að dyrasíminn hefði verið bilaður í þrjátíu daga — subordinate clause

Inside the subordinate clause:

• dyrasíminn — subject
• hefði verið — verb phrase
• bilaður — predicate adjective
• í þrjátíu daga — time expression

So the sentence is quite close to English word order here, even though the grammar inside it is more Icelandic.

Much less naturally than in English. In standard Icelandic, að is normally kept in sentences like this.

English:

• He said the intercom was broken.
• He said that the intercom was broken.

Icelandic strongly prefers:

• Hann sagði að dyrasíminn hefði verið bilaður.

So as a learner, it is safest to include að.

It describes a state: the intercom was in a broken condition for a period of time.

That is why bilaður works well here:

• the intercom had been broken for thirty days

This focuses on the condition lasting over time, not on the moment when it broke.

So the sentence is about duration of the broken state, not the exact breakdown event.